KS is a vascular tumor caused by infection with KSHV. The oropharynx plays a central role in KSHV infection. KSHV transmission occurs through saliva which, in sub-Saharan Africa, occurs at high rates beginning in eariy childhood. KSHV replication Is detected most frequently in the oral cavity, and oral viral replication is strongly associated with viremia. Therefore, understanding the biology and pathogenesis of oral KSHV infection appears critical to devising strategies to interrupt transmission and prevent spread throughout the host. This Clinical Core will enroll cohorts and collect biological specimens to support the Program Project, Oral pathogenesis and host interactions of Kaposi sarcoma-associated herpesvirus (KSHV) infection (PI Dr. Timothy Rose). The goal of the Clinical Core is to foster innovative translational research on KSHV infection, replication, pathogenesis and immunity through the collection of uniquely valuable biological specimens from KSHV-infected people in an area hyperendemic for KS. Cohorts will be enrolled at the Uganda Cancer Institute (UCI) in Kampala, Uganda through our outstanding collaborative research group, the Uganda Program on Cancer and Infectious Disease (UPCID). The Clinical Core will be responsible for the enrollment, evaluation, and follow-up of clinical cohorts at the UCI, and for obtaining and managing laboratory specimens for all four projects of this RFA. Aim 1 of the Clinical Core is to recruit, screen, and enroll KSHV-infected children and adults into research protocols in Kampala, Uganda. Study participants will be enrolled into studies by experienced UPCID research staff. Follow-up of participants will be performed in accordance with the ethical conduct of human subjects research, using proven methods to maximize adherence to study procedures. Aim 2 is to collect, process, and ship clinical specimens suitable for the study of; (1) KSHV infection of oral epithelial and lymphoid cells using oral tissue collected from routine tonsillectomies; (2) expression of phenotypic markers of angiogenesis and lymphatic differentiation in oral and cutaneous KS tumor biopsies; and (3) immune correlates of the control of KSHV infection using saliva and blood specimens collected from HIV-infected and uninfected subiects followed at the UCI.